According to Techcrunch Stumbleupon is for sale for $50 million

Two sources have confirmed that the rapidly growing StumbleUpon recently approached at least one large Internet company to be acquired. The asking price was $50 million.

The deal doesn’t appear to have been widely shopped - one potential acquiror said that they met with the company recently, but only to explore possible business development deals, and that an acquisition was not discussed. I spoke briefly with StumbleUpon CEO Garret Camp this afternoon but he refused to comment, saying “we do not comment on rumors.” Fair enough.

The real story may be a disconnect between the company’s executives and investors. StumbleUpon has only raised a single seed round of financing - $1.5 million - and angel investors often informally shop a company, with or without the company’s permission, in the hope of an early cash out.

Whatever is going on, StumbleUpon certainly isn’t stumbling in its growth. It is now a significant source of traffic for many startups (an entrepreneur recently told me that 15% of his traffic last week came from StumbleUpon). Garret told me today that the company has 1.5 million registered users and an average of 3.5 million page views per day. They expect to be cash flow positive within the next few months.